Apparatus for use in the electrolytic deposition of metal on metal tubes



Dec. 10, 1929.

F. J. PIKE ET AL APPARATUS FOR USE IN THE ELECTROLYTIC DEPOSITION OFMETAL ON METAL TUBES Filed Jan. 30, 1929 6 Sheets-Sheet Dec. 10, 1929.F. J. PIKE 'EI" AL 1,738,727

APPARATUS FOR USE IN THE ELECTROLYTIC DEPOSITION OF METAL ON METAL TUBESIIIII Fil Jan- 1929 6 Sheets-Sheet 2 I'::\ [292 i {w 5; 1;; I8 6 5 j E E21 Dec. 10, 1929. J, p E ET AL 1,738,727

APPARATUS FOR USE IN THE ELECTROLYTIC DEPOSITION OF METAL ON METAL TUBESFil an- 1929 6 Sheets-Sheet 5 Dec. 10, 1929. F. J. PIKE ET AL APPARATUSFOR USE IN THE ELECTROLYTIC DEPOSITION OF METAL 0N METAL TUBES FiledJan. 30, 1929 -6 Sheets-Sheet 4 rllivffflirlilvlllvflf IYlvrllviifflvllll i Ill/(I'IIVIIIIVIIIII Dec. 10, 11929.

APPARATUS Fon uss F. J. PIKE El AL 1,738,727

IN THE ELECTROLYTIC DEPOSITION OF METAL ON METAL TUBES Filed Jan. 50,1929 6 Sheets-Sheet 5 Dec. 10, 1929. F. J. PIKE El AL APPARATUS FOR USEIN THE ELECTROLYTIC DEPOSITION 0F METAL O N METAL TUBES Filed Jan. 30,1929 6 Sheet's-Sheet 6 Patented Dec. 10, 1929 UlTE STATES PATENT OFFICEFREDERIC JOHN PIKE, or BECKENHAM, AND C'YRIL JOHN LYTH, F WOOLWICH, LONON, ENGLAND, ssIG oRs T0 J. STONE & COMPANY LIMITED, or DEPTFORD,ENGLAND, A COMPANY or GREAT BRITAIN APPARATUS FOR USE IN THEELECTROLYTIC DEPOSITION OF METAL ON METAL TUBES Application filedJanuary 30, 1923, Serial No. 336,154, and in Great Britain November 30,1927.

This invention comprises improvements in apparatus for use in theelectrolytic deposiratus is described in which tubes of the kindreferred to are supported at a number of points along their length in acathode frame, and flexible anodes insulatedly supported in the frameare tensioned concentrically within the bores of the tubes. It isimportant when large numbers of tubes have to be coated, as is the casewhen condenser tubes are in question, to be able to load the framesquickly and with little trouble or liability to bend the tubes out ofstraightness. The principal object of these improvements is to provideframe construction-s which facilitate to a maximum degree the insertionand removal of large .numbers of slender tubes without liability ofimpairing their straightness but with firm support for preserving suchstraightncss and good contact with the cathode frame. A further objectis to provide advantageous fittings and arrangements for enabling theplated tubes to be washed in an efiicient manner whilst still in theframes used for supporting them inthe plating bath.

According to this invention, the tube-supporting members of the frameare formed with snaped slots, notches. or the like into which thetubesare entered most conveniently by a bodil movement laterally,clampingdevices, we gesor other suitable securing devices being appliedfor pressing the entered tubes against the seats-provided by the wallsof the slots, notches or the like, whereby the tubes are firmly held andsupported in good electrical contact with the frame. -A similaradaptation of frame members may be adopted for the lateral entering ofthe flexible anode rods.

According to a further part of the invention a washing chamber orcabinet is pro vided into which thelloaded frames can be readilyintroduced immediately after being elevated from a plating well and inwhich expense unnecessarily, and might be otherwise quite undesirable,to coat the tubes over the whole of their external surfaces.Consequently, it is important to devise means for enabling end portionsof the tubes to be coated externally as well as internally. In thespecification of the patent application Serial N 0. 222,829 aforesaid,the external coating of the ends simultaneously with the internalcoating of the bores of the tubes was proposed to be carried out by theaid of external anodes of ring form. The external appearance of a tubecoated in accordance with that process, however, did not exhibit a sharpline of demarcation between the coatings of the ends and the uncoatedlength lying between such ends, as there was a diffusion of thedeposited chromium due to the entire immersion of the tubes connected upas cathodes. These present improvements further provide for the externalcoating of the end portions of the tubes so that a sharp line ofdemarcation is obtained between the coated and uncoated portions. Forthis purpose, the tubes are supported in a vertically adjustable frameimmediately above a shallow bath or trough containing an anode and theelectrolyte and the frame is lowered to immerse the lower ends of thetubes to the correct depth so that the end portions receive a uniformdeposit which ceases sharply at the 7 surface of the electrolyte.

In order to enable this invention to be readily understood reference ismade to the accompanying drawings illustratingseveral examples of piecesof apparatus constructed in'accordance with these improvements, in whichdrawings l Figure 1 is a central vertical sectional ole-- 'vation of animproved frame loaded with tubes and anodes and suspended in anelectroplating pit.

Figure 2 is a detail plan view to'a larger scale of tube clips used onthe frame in Figure 1.

s rayduring an electroplating operation in t e it aforesaid.

Flgure 4 is a detail pla n view to a larger scale illustrating thefixing of the tubes by wedge devices on the frame of Figure 3.

Figure 5. is a sectional side elevation, Figure 6 is an end elevation,and Figure 7 1s a lan of washing apparatus to be employed in associationwith the electro-plating pit aforesaid.

. Fi ure 8 is aside elevation and Figure 9 is a ront elevation ofapparatus comprising risin and falling frames and fixed troughlike bathsfor electrosplating externally the ends of a number of tubes.

Figure 10 is a sectional side elevation to a larger scale of one of theelectro-plating baths and fragment of one of the frames seen in Figures8 and 9.

Figure 11 is a plan of Figure 10.

Figure 12 is aground plan of a plant comprising pieces of apparatusillustrated in the preceding figures.

Fi ures 13 and 14 are detail sectional views of tu liular extensions tobe fitted to the ends of tubes being plated when desired.

Referring to Figure 1, the electro-plating bath is advantageously in theform of a pit sunk in the ground and lined with a cylindrical metallining a, an acid tank I), which is the plating bath proper beingsuspended concentrically within the lining a and the intervening annularspace a being filled with cooling liquid such as water or supplied withsteam, hot water, oil or other fluid. The tubes to be plated, one isseen. at g, are supported upon a frame or long tubular structure, now tobe described, which is lowered into the bath 6. The said frame orstructure, comprises a long tube d encircled at a number of points alongits length by rings 6.

' Each ring 6 is formed peripherally with a number of seatings which maytake the form of notches in which are fixed small segments of cylindersf, Figure 2, of an internal diameter corresponding with the externaldiameter of the tubes 9 to be seated therein. If desired, however,V-shaped notches may be formed in the rings with uniform spacing aroundthe latter and such notches may be adapted for seating tubes ofdifferent diameters, whereas the segments 7' are suitable for tubes ofone diameter only. The rings 6 are mounted, of course, so that there isaccurate On these studs are screwed wing nuts j which are operative uponresilient clamp strips of suflicient length to extend across the twoadjacent seatings f when such strips 7r: are set at right angles to theaxis of the tube (1, as seen in Figure 2. If desired, resilient clampstrips may be perforated to pass over the studs h and may be securedtothe wing nuts 7' by rivets. With such a construction, the clamp stripsare turned to set them in the direction of the axis of the tube d,thereby freely opening the notches or seatings 7. Each tube 9 to beplated is then applied laterally to the frame structure so as to lielongitudinally thereof in a row of aligned notches or seatings Upon twoadjacent rows of such seating eing occupied by tubes, the correspondingclamp strips 70 are given a quarter turn to set them at right angles tothe tubes and to clamp or clip the latter in the seatings f, the wingnuts j being adjusted so that a sufficient clamping pressure isattained. If the strips 70 are fixed to the nuts j, the latter are givena preliminary adjustment to suit the size of the tubes and are finallyadjusted to bring the strips k to the desired clamping position.

A frame loaded with a number of condenser tubes is of substantial weightand in order to prevent damage to the clamping devices 70 by theswinging of the load in the plating pit or well, it is advantageous toprovide guard fins or ribs Z extending along the frame structure andprojecting radially outwards beyond the clamping devices. Such fins orribs Zmay be in the form of iron or steel bars applied edge-on to theperipheries of the rings 0 and suitably let into and may be welded inappropriate notches formed in such rings. i

The ends of the tubular frame structure 01 receive rings m m which aresecured thereto by welding. On the upper end, there is screwed anannular cap at which is further secured by brazing. To the lower end asteel disc 0 is fixed to the ring m by insulated bolts 12, nsulationdiscs 9 being interposed so that there is no electrical connectionbetween the disc 0 and frame (Z. To the top ring m and cap n are boltedseveral, say three, laterally extending brackets r, a gun metal cathodering 8 beinginterposed between the brackets r and the cap n. Thebrackets r extend outwards to such an extent that when the loaded frameis lowered into a plating pit or well, the said brackets come to restupon a ring casting t at the top of the acid tank I) and support theloaded frame therein, as secnin Figure 1. An anode disc u is connectedwith the ring m and cap at by insulated bolts 42 being spaced from thecathode ring 8 by sleeves w on the bolts 12. An anode terminal pillar a"extends vertically from an arm on a boss :11 bolted centrally to theanode disc u and a cathode terminal pillar 3 extends vertically from thecathode ring 8. Suspension eyes or loops 2, shown in dotted lines inFigure 1,

for raising and lowering the loaded frame, may be bolted to the anodedisc u, or the stems or legs or suspension eyes or loops might passthrough apertures in the disc 20 and be fixed, by screwing or bolting,to the annular parts 8 n m.

Flexible anodes 1, which may be of copper sheathed with lead, aretensioned between the anode disc u and the bottom disc 0 after beingpassed through the tubes 9. A nipple device 2 is fixed to the bottom endof each anode and is engaged with the disc 0, the upper end of eachanode being joined to a screw threaded rod 3 on which is screwed atensioning nut 4 bearing upon the anode disc ea. As will be seen fromFigure 1, the disc 0 and u are formed with peripheral notches so thatthe nipples 2 and nuts 4 may be engaged with the discs by lateralapplication of the anodes 1. The discs 0 and u are interchangeablymounted on the apparatus so that for tubes of any given diameter it ispossible to select and attach discs having .their notches suitablydisposed for supporting the anodes at the correct radial distance forcentering such anodes in their respective tubes g.

If it be desired to supply current to the lower ends of the anodes 1 aswell as to the upper ends through the anode disc u and nuts 4, aconductor 5 is brought down from the anode disc u and is electricallyconnected with the disc 0 as by the nut 6 which screws on to theconductor 5 and bears against the disc 0.

The conductor 5 may be a copper rod enclosed in a steel tube 7 which maybe welded at the bottom to the disc 0 and surrounded for the.

greater portion of its length by a tube 8 of ebonite in order to shieldthe anodic conductor 5 from the cathodic frame d.

A casing 9 surrounds the mouth of the well or pit, and is formed with afume exhaust connection 10, a suitable cover 11 being applied after theloaded frame has been lowered into the well.

According to the modified construction illustrated in Figures 3 and 4,the frame comprises a number of annular steel plates 12,

' spaced apart along a number of circularly disposed longitudinal beltsor rods 13, spacer sleeves 14 being conveniently employed for 'fiffthispurpose. These annular plates are all periphery with species of ingblocks 16 which are fixed by screws andv are formed withsemi-cylindrical seatings appropriate for the diameter of the tubes tobe seated. The annular plates 12 are mounted on the rods 13 so that anygiven slot in one plate is in accurate alignment or registration withthe corresponding and similar slots in other plates. Each tube 9 to beplated is presented laterally to the frame and passed through the stemsof a line of slots 15 into the enlargements of such slots, whereupon thetube is seated against the semi-circular seatings 16 inthebackwallsthereof. Steel wedges 17 are then passed endwise into theslotenlargements which they fit, the said wedges 17 being formedlongitudinally with grooves which are semi-circular in section to fitagainst the tubes. Pressing the wedges 17 home downwardly in the slotscauses the tubes 9 to be gently but firmly gripped so that the tube issupported at several points along its length in true alignment and ingood electrical contact with the plate members of the cathode frame.

In this modification, a top annular plate 12 is furnished with hooks 18for taking over an upward extension I) of the acid tank I) in order tosuspend the loaded frame in such tank, the latter being surrounded by awater space a as in Figure 1. A bottom annular plate 12 is spaced fromthe plate 12 latedly mounted on the rods 13 and spaced from the topframe plate 12 and from one another by suitable distance sleeves. Thedisc 20 carries the anode terminal pillar w and has its peripherynotched for the reception of screw threaded rods 3 attached to the upperends of the flexible anodes 1, tensioning nuts 4 being screwed on therods 3 and bearing upon the disc 20. The disc 21 is put into electricalconnection with the disc 20 through short gun metal bolts 22, and thisdisc 21 serves for the attachment of a central conductor 5 which extendsdown to the bottom of the frame where it is connected by a nut 6 with aconductor 23 attached to the plate 12 and extending inwards to thecentre of the frame. The conductor 5 is enclosed by a steel tube 7 whichis surrounded by ebonite 8 as in Figure 1. A third disc 24non-insulatedly mounted on the rods 13 andas seen clearly in Figure 4.

- prevent eddying or swirling of ode terminal pillar y and with asuspension eye 25 for raising and lowering the loaded frame. A coverdevice 26, with fume drawofl' connection 27 is fitted with bafiiedevices 28 adapted for intercepting acid spray and vapour. As shown inFigure 3, the connection 27 maybe jointed to an uptake 27 which includesa suction fan 27 a conical bafile 27 and collector chamber 27 to thedelivery of the uptake being suitably disposed for instance above a roofas in Figure 3".

The frame structures described with reference to Figures 1 to 4 can beloaded with tubes whilst lying on their sides or whilst standingvertically. The latter is preferable, as it saves the labour andpossible disturbance of the tubes involved in up-ending a horizontalloaded frame. The flexible anodes may be passed through the tubes whilstthe latter lie upon a bench prior to loading them into a frame. Thuswhen the tubes 9 are moved bodily laterally into their slots or seatingsin the frame, the respective anodes 1 are moved likewise so that thedevices on their ends laterally enter and engage with the peripheralnotches of the frame plates 0 u, Figure 1, or 12 and 12 Figure 3.

As Shown in Figure 18, the tubes 9 before being wedged on to the framemay have their ends fitted with short extension pieces 29 ofbrass orother tube having the same bore as the tubes 9 excepting that the boreis enlarged at one end for slipping friction tightly on to the tubes 9.These extension -pi es the .Qe "olyte in the extreme ends of the boresof the tubes 9 and thereby ensure internal'coating of the tubes right upto the extremities of their bores. a It is of importance to providemeans for expeditiously washing the frames and tubes after withdrawalfrom the plating well or bath. WVhile it is advantageous to have theplating baths sunk in the form of pits as above described, it would be avery expensive proceeding to sink additional pits for washing purposes,and moreover such washing pit-s entail labour and loss of time inlowering the frames into them and lifting them out again. Theseimprovements, therefore, provide a washing cabinet or chamber 30,Figures 5 to 7, in which the loaded frames, indicated diagrammaticallyat 31 in plan in Figure 7, can be readily introduced after beingelevated from a plating pit indicated at 32. The cabi net 30 is of thenecessary height to receive the said frame and may be provided withdoors 33 at its front. Down the sides, or in any other convenientposition, spray tubes 34 are fitted so that the frames and externalparts of the tubes can be sprayed and washed by water supplied to thetubes 34. The tubular extensions 29 which may be fitted to the tube endsas described with reference to Figure 13, may be fitted with lateralspigots 35,

Figure 14, for the attachment of hose con- I nections 36. Also, splitconed rubber or other plugs 37 may be applied to the anodes 1 and duringthe plating; operation may occupy the position seen inFigure 14, inwhich they remain elevated above the extensions 29 owing to their gripon the anode 1, thus leaving free the orifices of extensions 29 for theexit of the gases generated by the electrolyte action. When the platingis finished, a loaded frame is elevated from the plating pit to floorlevel and is deposited upon the floor.

Thereupon, an operator on an elevated staging lowers all the rubberplugs 37 and presses them in to the upper ends'of the extensions 29. Hethen connects thehoses 36 with the spigots 35. The loaded frame is thenintroduced into the cabinet 30 Figures 5 to 7 andthe water is turned onto the spray pipes 34 and also to the hose connections 36, so thatactive streams are introduced into the bores of the plated tubes for theefiicient washing thereof, at the same time that all external parts arewashed by the sprays from the spray pipes 34. If desired the spigots mayextend upwardly at an angle of about 60 to the extensions 29 and thelatter may have an annular end wall at the top to fit more or lessclosely around the anodes 1. With such an arrangement the plugs 37 canbe dispensed with.

Two or-more plating pits 32 may be disposed in the track of a travellerand also one or more washing chambers 30, so that the 1 washing of aloaded frame or frames may proceed whilst the plating of tubes in otherframes is in progress.

For externally coating the end portions of tubes, such as condensertubes which may require to be jointed in tube plates or metal walls asalread explained, the apparatus illustrated in Figures 8 to 11 isprovided; Frames 38 vertically slidable on a supporting frame 39 arecounterbalanced by weights 40 attached to cables passing over idlepulleys. Cross bars of these frames 38 are fitted with metal clips 41and with seating blocks 42, Figures 10 and 11, the tubes being pressedbetween the clips 41 and seated against the blocks 42. The clips 41 areelectrically connected together and with a suitable conductor to form acathode connection. Near the top of the fixed frame there are cross bars43 formed with guide holes for the upper end portions of the tubes, asseen in Figure 9, the upper ends of the tubes beinginserted into holesin the top bar of the movable frames 38. A trough-like bath 44 issupported on the fixed framing beneath each of the movable frames andthese baths are prefflanged so as to be supportable on insulation 47along the side edges of the trough and'perforated'for the passage of thelower ends of the tubes 9 carried by the movable frames.

An additional anode plate 46 may be carried underneath the lower ends ofthe tubes 9 and may be provided with upwardly pro jecting cylindricalbosses 46 one opposite the lower end of each tube g. These additionalanode plates and their bosses have for their purpose to cause thechromium to be thrown effectively on to the end surface of the tubes.

; able frames may serve as gauge bars, or other means may be employedfor ensuring that the lower ends of all tubes inserted in to the frame38 are at the appropriate level. The loaded frame is then lowered untilarrested by the stops on the rods 48, whereupon the lower ends of thetubes 9 are found to be immersed to the correct depth in the trough-likebath as seen in the right hand half of Figure 9. The current, beingswitched on, passes from the anode plate 46, to the tube ends andthrough the cathodic clips and the immersed ends are thus electroplated.If it be desired to plate the extremeedges or end faces of the tubes 9an anode strip may be suspended from the anode plate beneath the levelto which the lower ends of the tubes descend.

Figure 12 shows a ground plan of plant comprising apparatus of the kindhereinbefore described. 50 indicates benches upon which the tubes arelaid when the flexible anodes are passed through them. 51 indicates anelevated staging for operators attending to the upper ends of the tubesand frames the latter being loaded with tubes in the bay 52 adjacent tothe plating pit 32. A traveller lifts the loaded frame and deposits itin the pit 32, afterwards raising it again and delivering it into thewashing cabinet 30. After washing and removal from the cabinet 30, thetubes are unloaded from the frame. Any further treatment such aswashing, pickling the plating pit has been described with reference toFigure 3.

We claim 1. Apparatus for electroplating the bores .of tubes comprisingan elongated framing having spaced open seatings into which tubes areinsertable by lateral bodily approach, tube securing means adapted forholding the tubes tightly to their seatings, and anode mountings adaptedfor supporting elongated anodes Within the tubes.

2. Apparatus for electroplating the bores of long metal tubes,comprising an electrolyte container, an elongated tubular frame havingspaced members, tube-supporting means provided on the periphery of saidmembers, suspension means for said frame within the container, andlongitudinal guard ribs on the exterior of said frame.

3. Apparatus for electroplating the bores of metal tubes comprising anelectrolyte container, an elongated frame, having spaced rings formedwith'peripheral tube-seating slots, closure devices operative forretaining tubes in said seating slots, end anode plates formed withperipheral slots, tensioning means adapted for engaging the slots in saianode plates and operative for su porting and tensioning elongatedanodes within seated tubes and a longitudinal sheathed conductorconnected between said anode plates.

4. Apparatus for electroplating the bores of long metal tubes comprisingan electrolyte container, an elongated tubular frame composed of spacedrings formed with seating slots around their periphery, swivel clipsadapted for securing two adjacent tubes in their seatings, andtensioning means adapted for holding anode rods concentrically withinthe tubes.

FRED. J. PIKEF C. J. LYTH.

and marking of the tubes is performed in the tanks and on the benchindicated diagrammatically at the position 53 and theends of the tubesare plated externally in the baths

